This invention relates generally to protective bumper strip assemblies for protecting furniture edges, wall and display case surfaces and the like, and more particularly to an improved resilient bumper strip and mounting member for such assemblies. Protective strip assemblies using resilient strip materials in various types of channels are known in the art, as illustrated in U.S. Pat. Nos. 4,083,592, and 4,808,451 and the patents cited therein. The protective strip assembly disclosed in the U.S. Pat. No. 4,808,451, patent is shown in FIG. 1 and includes a metal channel capped by strip of a resilient material, such as rubber. The channel, which may be roughly rectangular in its outside cross-section, attaches to a surface to be protected. The resilient rubber strip surrounds and engages the channel along the channel faces that face generally perpendicular to the surface to be protected. The rubber strip therefore butts up against the surface to be protected, wholly concealing the channel. It may also be arranged to be flush with a surface perpendicular to the one to which it is attached.
The resilient strip of the prior art suffers from a number of drawbacks, illustrated with reference to the Figures. Referring to FIG. 1, a resilient strip assembly 10 is shown in perspective, showing a resilient strip 14 and a mounting member 18, with some portions of the resilient strip 14 removed. The resilient strip 14 is generally a semi-cylindrical body 22 which surrounds the mounting member 18 on three of its four sides. The mounting number 18 may be secured to the surface to be protected 26 by means of mounting screws shown representatively at 30 which secure the mounting member through hole 34.
Referring now also to FIG. 2, which shows the resilient strip 14 and mounting member 18 in cross section, it can be seen that the semi-cylindrical body 22 of the resilient strip is bounded by circumferentially facing edge portions 38. Radially extending latch members 42 extend radially inwardly from the semi-cylindrical body 22 at a location between the edge portions 38 and a point 45 degrees away from the mid-line 72 of the semi-cylindrical body 22. Radially extending latch members 42 extend longitudinally along the length of the resilient strip 14. Flanking each radially extending latch member 42 are a pair of radii 46 and 50. Radially projecting latch members 42 are hollow, each having a lumen 54 running along the length thereof. Lumens 54 facilitate assembling and disassembling the strip assembly, by providing a releasable spring retention force, as explained below.
With reference to FIGS. 2 and 5, the structure of the mounting member 18 may be seen. The mounting member 18 is used with both the resilient strip of the prior art and the resilient strip of the present invention. The present invention also includes an improved mounting member. The mounting member 18 of the prior art has a web portion 62, which includes a pair of oppositely disposed web latch extensions 66. When the mounting member 18 and resilient strip 14 are assembled, the web portion 62 extends across a chord of the semi-cylindrical body 22, substantially parallel to a tangent to the circumference of the semi-cylindrical body portion at its mid-line 72.
A pair of oppositely disposed, spaced apart leg members 76 extend from the web portion 62, away from the semi-cylindrical body 22. From each leg member 76 extends a base member 82. The base members 82 extend away from each other. Each base member 82 terminates in a base latch portion 86.
As oriented in FIG. 2, the web latch extensions 66 extend outwardly to a position closely adjacent but inward of an upward projection of the base latch portions 86 and the base latch portions 86 extend upwardly to a position closely adjacent but below an outward projection of the web latch extensions 66.
The mating of the resilient strip 14 of the prior art and mounting member 18 is also illustrated with reference to FIG. 2. The web latch extensions 66 of the web portion 62 are sized to extend to the semi-cylindrical body 22 adjacent the hollow radially inwardly extending latch portions 42. Likewise, the base latch portions 86 mate with the semi-cylindrical body 22 adjacent the other side of the hollow radially extending latch portions 42. Thus, each hollow radially extending latch portion 42 is clamped between a respective web latch extension 66 and base latch portion 86. Insertion is facilitated due to the presence of lumens 54, which permit snug retention of the strip 14 in the mounting member 18. As the resilient strip 14 is pressed against the mounting member 18, the leading edges of the hollow radially extending latch members 42 wedge between web latch member 66 and base latch member 86, which latch members squeeze together the walls of the hollow radially extending latch member 42.
As will be understood, the shortest distance N (FIG. 5) between web latch extension 66 and base latch portion 86, perpendicular to the path of insertion of radially extending latch member 42 (parallel to the arrow I), should be smaller than the width of fully expanded hollow latch member 42, to impede removal. Further, the space W beyond the narrowest spot N should be wider than the narrowest distance to permit the radially extending latch member 42 to expand after insertion, thereby locking itself in place. The compressibility of the lumens 54 permit this expanding locking engagement. If hollow latch members 42 were solid and still of the same cross-sectional dimensions relative to the mounting member 18, it would take a great force to compress the solid resilient material of latch member 42 so that it could be inserted through the narrow gap N.
While the lumens 54 facilitate engagement, they create other problems. Resilient strips 14 are typically manufactured by extrusion. It is relatively difficult to uniformly extrude long sections having long hollows, such as the lumens 54. The width of the outside dimension of the latch extension 42 varies unacceptably, as does the wall thickness and thus the size of the lumen 54. As will be understood, the dimensions of the lumens 54 determine the degree of force required to engage the resilient strip 14 and the mounting member 18, and also the degree of force that will dislodge the strip 14 from the mounting member 18 once engaged. The variations in lumen dimensions that arise under commercially reasonable extrusion conditions are unacceptably great: some production runs of the strips 14 must be scrapped because they cannot be engaged with the mounting member 18, and others must be rejected because they engage the mounting member too loosely. Variations from one extreme to the other also can arise along the length of a single extruded strip.
Another drawback relates to the fit between the elongated resilient strip 14 and accessories, such as corner pieces and connectors. FIG. 3 illustrates a corner assembly for use with the prior art and the claimed invention with some parts of the strip removed and some not shown. The corner assembly includes a corner piece 250 and an adaptor 252. Each piece has a virtually identical mounting portion 256, 258, which engages resilient strip 14. The corner piece 250 has a slotted quarter spherical head portion 260. The adaptor has a head portion with a curved tongue 262 of a size and shape to fit within the slot of the head on the corner section 260. The terminal portion of the tongue and the deepest most recess of the receptacle are congruently shaped to provide a positive engagement achieved upon the resilient locking of the fully inserted tongue into the slotted head. The corner assembly is described fully in U.S. patent application Ser. No. 383,763, entitled "Corner Assembly for Flush Fitting Protective Strip Assembly," filed in the name of Myron Ullman concurrently herewith which is hereby incorporated by reference herein.
As shown with reference to FIG. 4, it is desirable for the terminal edge 280 of strip 14 to mate smoothly with the edge 282 of quarter spherical head 260, as shown at S. However, due to the difficulties of molding the latch extensions 42, the outside dimension of the strip 14 is often irregular, typically flaring out into a "hip" adjacent the radial latch extension 42. Consequently, the mating between the edge 280 of strip 14 and edge 282 of quarter spherical head 260 is uneven, as shown at U. This creates a sloppy appearance and is thus, undesirable.
Thus, some of the principal objects of the invention are: to provide a protective strip assembly that permits the resilient strip to extend to flush up against the surface to be protected; to provide a strip that may be manufactured reliably and consistently; to provide a strip that engages reliably with a mounting member; to provide a strip having a controllable outside dimension that fits flush with corner assemblies and other accessories; and to provide a flush mounting strip assembly that is inexpensive to make and that may be easily and confidently assembled.